net: vrf: move to generic dstat helpers

The vrf driver has its own dstats-to-rtnl_link_stats64 collection, but
we now have a generic implementation for dstats collection, so switch to
this.

In doing so, we fix a minor issue where the (non-percpu)
dev->stats->tx_errors value was never collected into rtnl_link_stats64,
as the generic dev_get_dstats64() consumes the starting values from
dev->stats.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240607-dstats-v3-3-cc781fe116f7@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/vrf.c

@@ -137,33 +137,6 @@ static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
 	kfree_skb(skb);
 }
 
-static void vrf_get_stats64(struct net_device *dev,
-			    struct rtnl_link_stats64 *stats)
-{
-	int i;
-
-	for_each_possible_cpu(i) {
-		const struct pcpu_dstats *dstats;
-		u64 tbytes, tpkts, tdrops, rbytes, rpkts;
-		unsigned int start;
-
-		dstats = per_cpu_ptr(dev->dstats, i);
-		do {
-			start = u64_stats_fetch_begin(&dstats->syncp);
-			tbytes = u64_stats_read(&dstats->tx_bytes);
-			tpkts = u64_stats_read(&dstats->tx_packets);
-			tdrops = u64_stats_read(&dstats->tx_drops);
-			rbytes = u64_stats_read(&dstats->rx_bytes);
-			rpkts = u64_stats_read(&dstats->rx_packets);
-		} while (u64_stats_fetch_retry(&dstats->syncp, start));
-		stats->tx_bytes += tbytes;
-		stats->tx_packets += tpkts;
-		stats->tx_dropped += tdrops;
-		stats->rx_bytes += rbytes;
-		stats->rx_packets += rpkts;
-	}
-}
-
 static struct vrf_map *netns_vrf_map(struct net *net)
 {
 	struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
@@ -1201,7 +1174,6 @@ static const struct net_device_ops vrf_netdev_ops = {
 	.ndo_uninit		= vrf_dev_uninit,
 	.ndo_start_xmit		= vrf_xmit,
 	.ndo_set_mac_address	= eth_mac_addr,
-	.ndo_get_stats64	= vrf_get_stats64,
 	.ndo_add_slave		= vrf_add_slave,
 	.ndo_del_slave		= vrf_del_slave,
 };